JP6516566B2 - Dehumidifying dryer - Google Patents

Description

  The present invention relates to a dehumidifying and drying apparatus for drying a material to be dried by dehumidifying air in a drying chamber containing food and other materials to be dried such as fish, shellfish, meat, vegetables and fruits.

  The dehumidifying and drying apparatus promotes the evaporation of the water in the material to be dried to perform drying by reducing the relative humidity of the air in the drying chamber containing the material to be dried. As the dehumidifying and drying apparatus, a heat pump type medium temperature air cooler (hereinafter referred to as "middle temperature machine") in which the evaporation temperature (dew point) of the refrigerant is set to -5 to -15.degree. C. is widely used.

  A conventional general dehumidifying and drying apparatus uses a medium temperature machine alone, and air in the drying room (hereinafter referred to as "air in the room") is sucked from the inside of the drying room to the medium temperature machine, and the medium temperature machine By passing the evaporator and the condenser in series, the entire amount is blown back into the drying chamber. In such a dehumidifying and drying apparatus, the temperature of the air in the storage rises by the operation.

  In order to further lower the relative humidity of the reachable interior air, an apparatus provided with two systems of medium-temperature and low-temperature air coolers has also been proposed (Patent Documents 1 to 3). The dehumidifying and drying device of the mid-temperature unit alone can dry the material to be dried up to about 30% of the relative humidity of the air in the storage. On the other hand, the dehumidifying and drying apparatus equipped with the medium- and low-temperature air coolers can reduce the relative humidity of the air in the storage to about 20%.

Japanese Patent Application Laid-Open No. 52-48155 Japanese Utility Model Application Publication No. 58-126622 JP 2002-228188 A

  In order to dry the food quickly, the temperature should be raised, but with fish and shellfish, the food will deteriorate. In freeze-drying, the taste changes. Although normal temperature drying is the best, it has the disadvantage that it takes time to dry.

  Since the saturated water vapor pressure decreases as the air temperature decreases, the heat exchanger on the heat absorption side of the air cooler (evaporator, hereinafter simply referred to as the “heat exchanger”) in order to lower the relative humidity of the air in the cold storage In other words, the heat exchanger on the heat radiation side may be called a "condenser." However, if the temperature of the heat exchanger is lowered (for example, -30 ° C), the water vapor in the air adheres to the heat exchanger to block the passage of air, and the thermal conductivity also decreases, so the drying is very long. It takes time and limits the value of relative humidity that can be achieved, which is difficult to achieve below 18%.

  As a method to solve this problem, it is conceivable to lower the temperature of the heat exchanger in accordance with the relative humidity of the air in the storage which decreases with the progress of drying, but depending on the type of food and the amount of water The problem is that the system structure and control become complicated, for example, it is necessary to provide a plurality of air coolers and a plurality of air flow paths to detect the relative humidity of the passing air while switching them. .

  The present invention is to provide a food dehumidifying / drying apparatus capable of reducing the relative humidity of the air in the storage to a single digit level without switching the heat exchanger and the air flow path in the middle of the drying process with a simple structure. It is an issue.

  The dehumidifying and drying apparatus of the present invention includes an air cooler in which the heat exchanger 3 is divided into a water droplet adsorption area (medium temperature side) 32 and a frost adsorption area (low temperature side) 31 (31a, 31b). The heat exchanger 3 is provided such that most of the circulating air circulating in the dehumidifying and drying apparatus passes through the water droplet adsorption area 32 and the frost adsorption area 31 in this order, and a part passes twice through the frost adsorption area. Be

  The heat exchanger 3 is provided to shield the air flow path. The passing air passes through the mesh formed by the refrigerant tubes 33 and 34 and the heat absorbing fins 38, but frost adsorption is performed so that the condensed water droplets flow down along the fins 38 or the refrigerant tubes 33 and 34. It is provided vertically with the area 31 upward. The area of the water droplet adsorption area 32 is preferably larger than the area of the frost adsorption area 31, and the circulating air passing through the water droplet adsorption area 32 and the frost adsorption area 31b adjacent to the water droplet adsorption area is inverted to It is rational to form a circulation air flow path so as to pass through the upper portion 31a.

  In the frost adsorption area 31b adjacent to the water droplet adsorption area 32, a large amount of frost adheres at the initial stage of the drying process, but heat transfer from the water droplet adsorption area 32 suppresses the adhesion of frost and dehumidification ability Too big. Even if this portion is closed by frost, the internal air circulates through the water droplet adsorption area 32, so the dehumidification capability is not significantly reduced. On the other hand, since the air dehumidified in the water droplet adsorption area 32 passes through the upper part 31a of the frost adsorption area, the adhesion of frost is suppressed.

  The refrigerant discharged from one refrigerant compressor 45 is supplied to the water droplet adsorption area 32 and the frost adsorption area 31 of the heat exchanger 3, and the amount of refrigerant passing through the frost adsorption area 31 passes through the water droplet adsorption area 32. A regulator 37 is provided which regulates the amount of refrigerant. The expansion valves 35 and 36 are provided at the inlets of the refrigerant pipes 33 and 34 of the frost adsorption area 31 and the water droplet adsorption area 32, respectively, and the refrigerant temperature of the frost adsorption area 31 is lower than the refrigerant temperature of the water droplet adsorption area 32 It can be set.

  A turntable 11 is provided in the drying cabinet 1, and by rotating the accommodated drying object w in the drying cabinet 1, the accommodated drying object is uniformly dried. For example, when the object to be dried such as kelp is hung and dried, the turntable 11 is provided on the ceiling of the drying cabinet 1.

  The main heater 5 for setting the temperature inside the storage to a desired temperature is provided in the return path 22 of the air that has passed through the heat exchanger 3, and the dehumidified air heated by this heater flows into the drying storage 1 Do. The interior temperature to be set varies depending on the type of food to be dried, and is preferably around 15 ° C. for fish and shellfish, but the food with high sugar content can be made about 50 ° C. to accelerate the drying rate.

  The dehumidifying and drying apparatus of the present invention preferably includes an inverter-controlled auxiliary blower 7 for adjusting the proportion of air passing through the water drop adsorption area 32, in addition to the blower 2 for circulating the inside air. Furthermore, it is more preferable to provide an auxiliary heater 8 for heating the air passing through the auxiliary blower 7. The frost adsorption is performed by controlling the motor of the auxiliary blower 7 by inverter control and adjusting the ratio of the amount of air passing through the water drop adsorption area 32 to the amount of air passing through the frost adsorption area 31 b adjacent to the water drop adsorption area 32. The amount of frost adhering to the area 31 can be adjusted, and the operating conditions can be finely adjusted.

  The auxiliary heater 8 for heating the air of the auxiliary blower 7 may not be necessary, but when drying at a low internal temperature of around 15 ° C., it is more efficient to warm the discharge air of the auxiliary blower 7 a little. be able to.

  When the entire surface of the heat exchanger 3 of the air cooler is brought to -15 [deg.] C., the humidity decreases to some extent (about 18%), but does not decrease further. If the entire temperature is -30 ° C, the heat exchanger freezes in the early stage of drying, the heat conduction deteriorates, and the flow path area of air also decreases, so drying takes time and defrosting of the heat exchanger is also necessary. .

  In the present invention, the heat exchanger is divided into upper and lower parts, and the upper part is the frost adsorption area (about -30 ° C), and the lower part is the water drop adsorption area (about -15 ° C). It is possible to solve the capacity decrease only by the frosted area (-30 ° C) which tends to occur at the time of operation only by itself, and the insufficient drop of the humidity inside the chamber only by the water drop area (around -15 ° C).

  By dividing the heat exchanger into a water droplet adsorption area and a frost adsorption area, the steam turns into water and flows down in the water droplet adsorption area, and in the frost adsorption area after passing through it, the steam becomes a frost and is dehumidified. When drying progresses and the humidity in the storage decreases, dew condensation hardly occurs in the water drop adsorption area, and dehumidification is performed only in the frost absorption area, and the relative humidity of the storage air is adjusted to about It can be lowered to around 4%.

  Furthermore, by the combined use of the divided structure of the heat exchanger 3 and the auxiliary blower 7, it is possible to cope with more various objects to be dried and at the same time to further shorten the drying time.

Cross-sectional side view showing one embodiment of the present invention A plan view of part A of FIG. 1 A plan view of part B of FIG. 1 Front view showing a refrigerant pipe of a heat exchanger

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The dehumidifying and drying apparatus according to the embodiment shown in the figure is provided with a turntable 11 on the bottom of the drying cabinet 1. The turntable 12 is stacked with the objects to be dried w. The turntable 11 is guided on its outer periphery by a plurality of guide rollers 13 and is rotated slowly by a motor 14 with a reduction gear. The object to be dried w is stored on the turntable 11 in order to ensure that the whole is uniformly dried. The drying cabinet 1 is provided with a door 15 for carrying in and out the material to be dried.

  In the drying cabinet 1, the ceiling part thereof and the right part of FIG. 1 are separated by a partition wall 16, and a return passage 22 of circulating air and a suction passage 23 of the blower 2 are formed. In the illustrated apparatus, four blowers 2 are provided. On the left side of FIG. 1 of the drying cabinet, a reverse path 21 of circulating air is defined by the heat exchanger 3 of the air cooler. The main body 41 of the air cooler is installed in the space partitioned by the partition walls 42 and 43, and the condenser 44 is installed outside the drying cabinet, and the main body of the air cooler 41 and the condenser 44 is It is designed so that the temperature inside the cabinet is not affected by the heat radiation.

  The internal air flows from the right to the left in FIG. 1 by the blower 2, passes through the heat exchanger 3, flows upward through the reverse path 21, and then reverses to turn over again the upper portion 31 a of the heat exchanger 3. Through the return passage 22 to the suction passage 23 and circulate to the blower 2.

  The plate-like heat exchanger 3 includes an upper frost adsorption area 31 in which the low temperature pipe 33 is disposed, and a lower water drop adsorption area 32 in which the intermediate temperature pipe 34 is disposed. The low temperature pipe 33 and the medium temperature pipe 34 are both refrigerant pipes, and the refrigerant discharged from the same refrigerant compressor 45 is branched and flows in through the respective expansion valves 35 and 36. The pressure of the refrigerant in the frost adsorption area 31 is lower than the pressure of the refrigerant in the water drop adsorption area 32, so the refrigerant temperature in the frost adsorption area 31 is lower than the refrigerant temperature in the water drop adsorption area 32.

  At the outlet of the medium temperature pipe 34, a regulator 37 for adjusting the amount of refrigerant passing through the frost adsorption area 31 and the amount of refrigerant passing through the water droplet adsorption area 32 is provided. The refrigerant that has passed through the middle temperature pipe 34 is lowered to the refrigerant pressure of the low temperature pipe 33 by the regulator 37 and joins with the refrigerant of the low temperature pipe 33. By passing through the regulator 37, the pressure of the refrigerant in the water droplet adsorption zone is reduced to the same pressure as the pressure of the refrigerant in the frost adsorption zone 31.

  The regulator 37 regulates the ratio between the amount of refrigerant passing through the frost adsorption area 31 and the amount of refrigerant passing through the water droplet adsorption area 32. In the embodiment, the regulator 37 is provided at the outlet of the medium temperature tube 34, but may be provided at the outlet of the low temperature tube 33 or may be provided at the inlet side of the refrigerant tubes 33, 34.

  In the dehumidifying and drying apparatus of the embodiment, the opening degrees of the expansion valves 35 and 36 are set such that the surface temperature of the frost adsorption area 31 is -30 ° C and the surface temperature of the water drop adsorption area 32 is -15 ° C. The heat absorption fins 38 of the heat exchanger 3 are integrally provided without being divided by the frost adsorption area 31 and the water droplet adsorption area 32.

  The partition 16 which divides the dry storage 1 and the return path 22 is located above the boundary s of the frost adsorption area 31 and the water drop adsorption area 32. Circulating air passes through the heat exchanger 3 once and flows into the reverse path 21, then reverses, passes again through the upper part 31 a of the frost adsorption area 31 of the heat exchanger, and flows into the return path 22. Since the boundary s between the frost adsorption area 31 and the water droplet adsorption area 32 of the heat exchanger is located below the partition wall 16, part of the circulating air is the frost adsorption area 31b adjacent to the water droplet adsorption area and the upper part thereof. After flowing into the return path 22 through the frost adsorption area 31a, most of the circulating air passes through the water drop adsorption area 32 due to the area difference, and then passes through the upper portion 31a of the frost adsorption area 32 to the return path 22 Flow into

  In the water droplet adsorption area 32, the water vapor condensed on the heat exchanger 3 flows down along the heat absorption fins 38 and flows into a water receiver 39 provided below it. In the frost adsorption area 31, water vapor in the air adheres to the surfaces of the heat absorption fins 38 and the refrigerant pipe 33 as frost and adheres, but in the frost adsorption area 31b adjacent to the water droplet adsorption area 32, a part thereof becomes water droplets It flows down and adhesion of frost is suppressed. In the dehumidifying and drying apparatus of the embodiment, the lower two thirds of the heat exchanger 3 is a water droplet adsorption area 32, and the upper one third is a frost adsorption area 31.

  In the return path 22, the sterilizer 6 and the main heater 5 are disposed. The main heater 5 is an electric heater, and controls the current flowing through the main heater 5 according to the detected temperature of a not-shown thermistor installed in the storage, thereby maintaining the inside temperature at the set temperature. The air heated by the main heater 5 and whose relative humidity is lowered is blown out into the drying chamber by the blower 2.

  An auxiliary blower 7 that discharges air toward the water droplet adsorption area 32 of the heat exchanger and an auxiliary heater 8 that heats the discharge air of the auxiliary blower are provided in the air outflow side lower portion of the drying cabinet 1 There is. The auxiliary blower 7 is driven by an inverter motor, and can adjust the discharge air volume. As described above, a part of the circulating air passes through the frost adsorption area 31 twice and is circulated. By driving the auxiliary blower 7, the amount of air passing through the water drop adsorption area 32 is increased. Further, by energizing the auxiliary heater 8, the temperature of the air passing through the upper portion 31a of the frost adsorption area can be adjusted, and the amount of frost adhesion in the frost adsorption area 31 can be adjusted.

  The operating conditions of the dehumidifying and drying apparatus configured as described above are set by the set temperature of the main heater 5, the adjuster 37 of the heat exchanger 3, and the air volume of the auxiliary blower 7. These are adjusted according to the type of food and moisture content, but it is not necessary to change these set values from the beginning to the end of drying.

  The inside temperature is preferably about 15 ° C. to 50 ° C., and the fish and shellfish should be dried at about 15 ° C. Sugar-rich foods can be dried at high temperatures. The air cooler main body 41 and the condenser 44 are installed separately from the drying case so that the temperature inside the case is not affected by the heat generation of the air cooler main body 41 and the condenser 44, so that the temperature inside the room is low (15 ° C. The drying operation can be performed according to the type of food by freely setting it from the back and forth) to a relatively high temperature (about 50 ° C.).

  The regulator 37 of the heat exchanger 3 adjusts the region under the heat exchanger to be about -15 ° C and the region above the heat exchanger to be about -30 ° C. Although the air volume of the blower 2 may be constant, it is preferable to reduce the air volume when the temperature inside the container is raised, and therefore it is better to make it variable when drying various kinds of food. However, drying of the fish and shellfish leaves a smell, so as a matter of fact, either of them is dedicated, in which case the blower air volume may be constant.

  In the dehumidifying / drying apparatus of the present invention, dehumidification is mainly performed in the water droplet adsorption area 32 at the beginning of the drying process, and dehumidification is hardly performed in the water droplet adsorption area 32 at the end of the drying process where relative humidity decreases. Dehumidification is performed in the frost adsorption area 31. That is, in the early stage of drying where drying is performed without lowering the relative humidity so much, the moisture adsorption area 32 is mainly dehumidified, and at the end of the drying process where the relative humidity is lowered, the humidity is dehumidified in the frost adsorption area set at a low temperature In the final stage of drying, the relative humidity in the storage can be sufficiently reduced, and moreover, the frost adhering to the heat exchanger 3 can be suppressed, and drying at a temperature close to normal temperature can be performed efficiently. It will be possible to do.

DESCRIPTION OF SYMBOLS 1 dry storage 2 blower 3 heat exchanger 5 main heater 7 auxiliary blower 8 auxiliary heater 11 turntable 22 air return path 31 (31a, 31b) frost adsorption area 32 water droplet adsorption area 33 low temperature pipe 34 middle temperature pipe 35, 36 expansion valve 37 Regulator 38 Heat absorption fin 45 Refrigerant compressor w Dry matter

Claims (11)

A drying chamber for storing food to be dried, a flow path through which air in the drying chamber circulates, a heat exchanger for removing water vapor in the air in the flow path, and air cooled by the heat exchanger In a food dehumidifying and drying apparatus provided with a heating heater,
The heat exchanger includes a water droplet adsorption area for removing water vapor in the passing air as condensed water, and a frost adsorption area for freezing and removing the water vapor in the passing air ;
Ru part of the circulating air is guided to above the frost adsorption zone after passing the該霜adsorption zone adjacent to the water droplets adsorption zone, food dehumidifying and drying apparatus.   The dehumidifying / drying apparatus according to claim 1, wherein the flow path is configured such that circulating air which has passed through the water droplet adsorption area is guided to the frost adsorption area.   The dehumidifying / drying apparatus according to claim 1, further comprising: a regulator that adjusts a ratio of refrigerant passing through the water droplet adsorption area and the frost adsorption area. Most of the circulating air Ru is guided to after the frost adsorption zone that has passed through the water droplets adsorption zone, the dehumidifying and drying apparatus according to any one of claims 1 to 3.   The dehumidifying and drying apparatus according to any one of claims 1 to 4, further comprising a blower for circulating the air in the flow path.   The dehumidifying and drying apparatus according to any one of claims 1 to 5, wherein the frost adsorption area comprises an air flow path smaller than the water droplet adsorption area.   The dehumidifying / drying apparatus according to any one of claims 1 to 6, further comprising an auxiliary blower that adjusts the amount of air passing through the water droplet adsorption area.   The dehumidifying and drying apparatus according to claim 7, wherein the auxiliary blower is driven by an inverter motor.   The dehumidifying / drying apparatus according to claim 7, further comprising an auxiliary heater configured to heat discharge air of the auxiliary blower.   The manufacturing method of dry food which includes the process of dehumidifying and drying food by the dehumidifying and drying apparatus according to any one of claims 1 to 9. The method according to claim 10, wherein the food is at least one selected from the group consisting of seafood, meat, vegetables and fruits.

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